Estimation of anti-D IgG in red blood cell eluates using the specific radioactivity of 125I-labeled IgG: effect of unlabeled, cytophilic IgG.
The specific radioactivity of conventionally prepared 125I IgG anti-D eluates is significantly less (from 1/5 to 1/20) than that of the 125I IgG fraction used to prepare the eluate. This discrepancy is due to the release of unlabeled, cytophilic IgG from normal red blood cells during eluate preparation and does not represent an underestimation of the eluate anti-D IgG content. Cytophilic IgG content of eluates plays an important role in reducing the nonimmunologic binding of labeled antibody IgG. The results justify the assumption used in numerous studies that the specific radioactivity of 125I IgG fractions can be used to provide a valid estimate of the anti-D IgG content of eluates.
D003602:Cytotoxicity, Immunologic; D006801:Humans; D005779:Immunodiffusion; D007074:Immunoglobulin G / Q000032:analysis* / Q000276:immunology; D007457:Iodine Radioisotopes; D008722:Methods; D012204:Rh-Hr Blood-Group System
D007074:Immunoglobulin G; D007457:Iodine Radioisotopes; D012204:Rh-Hr Blood-Group System